2003 HONDA CIVIC coolant temperature

ECM ldle Learn Procedure
The idle learn procedure must be done so the ECM can
learn the engine idle characteristics.
Do the idle learn procedure whenever you do any of
these actions:. Disconnect the battery.
Replace the ECM or disconnect its connector.
Reset the ECM.
NOTE: Erasing DTCS with the Honda PGM Tester
does not require you to do the idle learn procedure.
Remove the No.6 ECU {ECM) ( 15A) fuse from the
under-hood fuse/relay box.
Remove the No.19 baftery (80A) fuse from the under-
hood fuse/relay box.
Remove PGM-FI main relay 1.
Remove any of the wires from the under-hood fuse/
retay Dox.
Disconnect any of the connectors from the under
hood fuse/relay box.
Disconnect the connector between the engine
compartment wire harness and ECM wire harness.
Disconnect the G2 terminal from the transmission
ho u srng.
Disconnectthe G'l terminal from the body.
Disconnectthe G101 terminal from the cylinder head
cover.
Procedure:
To complete the idle learn procedure, do this:
1. Make sure all electrical items (Ay'C, audio, rear
defogger, l:ghts, etc.,) are off.
2. Start the engine, and hold it at 3,000 rpm with no
load {in neutral) until the radiator fan comes on, or
until the engine coolanttemperature reaches 194"F(90'c).
3. Let the engine idle for about 5 minutes with the
throttle fully closed.
NOTE: lf the radiator fan comes on, do not include its
running time in the 5 minutes.
11-139

Intake Air Bypass GontrolThermalValve Test
Special Tools Required
Vacuum Pump/Gauge,0 30 in. Hg A973X-041-XXXXX
1. Stan the engine. Then let it idl€.
NOTE: The engine coolant temperature must be
below 149'F (65'C).
2. Remove the vacuum hose (A)from the intake air
duct, and connect a vacuum pump/gauge to the
nose.
3. Raise and lowerthe engine speed. and make sure
the vacuum gauge reading changes as the engine
speeo cnanges.
lf the vacuum reading does not change, check for
these problems:
. Misrouted, leaking, broken, or clogged intake air
bypass control system vacuum lines.. A cracked or damaged intake air bypass control
thermal valve.
4. Hold the engine at 3,000 rpm with no load (in
neutral) until the radiator fan comes on, then let it
id le.
5. Raise and lower the engine speed, and make sure
the vacuum gauge reading does not change as the
rpm cnanges.
lf the vacuum reading changes, check for these
proorems:
. l\4isrouted, leaking, broken, or clogged intake air
bypass control system vacuum lines.. A cracked or damaged intake air bypass control
thermal valve.
11-161

EVAP System
DTC Troubleshooting (cont'dl
31. While monitoring FTP sensor voltage with theHonda PGM Tester, or measuring voltage betweenECM connector terminals E4 and E14, slowly pump
the vacuum oumD.
ECM CONNECTOR E 13lPI
Wire side ot female terminals
32. Continue to pump vacuum until the voltage drops
to about 1.5 V. Make sure the engine coolant
temperature is still above 95'F 135.C) and your
vacuum pump has no leak.
33. Monitor the voltage for 20 seconds.
Does the voltage drop 1.5V and hold for at least
20 seconds?
YES Inspect the EVAP canister vent shut valve
line and connections.l
NO-Go to step 34.
34. Turn the ignition switch OFF.
35. Discon nect the quick-con nect fitting (A) fromthe
EVAP canister, and plug the canister port {B).
36. Turn the ignition switch ON (ll).
11-184
42. Turn the ignition switch ON (ll).
I
38.
39.
37. While monitoring FTP sensor voltage with theHonda PGM Tester, or measuring voltage betweenECM connector terminals E4 and E 14, slowly pump
the vacuum pump.
ECM CONNECTOR E {31PI
Wire side of lemale terminals
Continue to pump vacuum until the voltage drops
to about 1.5V. Make sure the engine coolant
temperature is still above 95"F (35"C) and your
vacuum pump has no leak.
Monitor the voltage for 20 seconds
Does the voltage hold for at least 20 seconds?
YES Inspecl the fuel tank vapor control lineand
connections.I
NO Go to step 40.
Turn the ignition switch OFF.
Disconnect the purge line hose {A) from the
canister at the metal line and plug the hose (B).
40.
41.

43. While monitoring FTP sensor voltage with the
Honda PGM Tester, or measuring voltage between
ECM connector terminals E4 and E14, slowly pump
the vacuum pump.
ECM CONNECTOR E {31P)
Wire side of female terminals
Continue to pump vacuum until the voltage drops
to about 1.5V. Make sure the engine coolant
temperature is still above 95'F (35'C) and your
vacuum pump has no leak.
Monitor the voltage continuously for 20 seconds.
Does the voltage drop to 1.5 V and hold f or at
least 20 seconds?
YES Inspect the EVAP canister purge valve line
and connections. lf they are OK, perform the EVAP
two way valve test (see page 11-186) and the fuel
tank vapor control valve test (see page 1'l-187) l
NO-Replace the EVAP canister
(see page 11-189).1
44.
45.
11-185

Heating and Air Conditioning
Radiator and Condenser Fans
Common
(cont'dl
Circuit Troubleshooting
9. Using a Backprobe Set, measure the voltage
between the No. 6 terminal of ECN4 connector B
{24P) and body ground with the ECM connectors
connecteo.
ECM CONNECTOR B {24P}
ls there battery voltage?
YES UDdate the ECM if it does not have the latest
so{tware, or substitute a known-good ECM, then
recheck (see page 11-6). lf the symptom/indication
goes away with a known-good ECM, replace the
original ECM.I
NO Repair open in the wire between the radiator
fan relay, the condenser fan relay and the ECM. t
Wire side of female terminals
21-30
Compressor Clutch Circuit
Troubleshooting
1. Check the No. 1 (20A) fuse in the under-hood
fuse/relay box, and the No. 14 {10A)fuse in the
under-dash fuse/relay box.
Are the tuses OK?
YES Go to step 2.
NO Replace the fuse(s), and recheck.I
2. Check the engine coolant temperature, the throttleposition sensor, and the idle speed (use the Honda
PGM Tester PGM-Fl data list if possible).
ls the coolant temperaturc above nomal, the
throttle position sensor rcading too high, or the
idle speed too low?
YES Troubleshoot and repair the cause of the
high engine coolant temperature, high throttle
position sensor reading, or low idle speed.l
NO-Go to step 3.
3. Remove the compressor clutch relay from the
under-hood fuse/relay box, and test it (see page 22-
51 ).
ls the relay OK?
YES Go to step 4.
NO Replace the compressor clutch relay.I
4. Measure the voltage between the No. 2 terminal of
the compressor clutch relay 4P socket and body
ground.
\
COMPfiESSON CLUTCH BELAY 'P SOCKET
ls there battery voltage?
YES Go to step 5.
NO Replace the under-hood fuse/relay box.I

\Body Electrical
Body ElectricalSpecialToolsGeneral Troubleshooting tntorrnaiion.'......
Relay and Control Unit Locations .....
Connectors and Harnesses
Fuse/Relay Boxes ...............................
Power Distribution .............................
Ground Distribution ...........................
Under-dash Fuse/Relay Box ..............
Battery ..............
Relays ................
*lgnition Switch ..............
*Gauges
Component Location Index .......................Self-diagnostic Procedure ..........................Circuit DiagramGauge Bulb Replacement ..........................Gauge Assembly ReplacementCoolant Temperature
Gauge Troubleshooting .... ....................Vehicle Speed Signal CircuitTroubleshootingVSS Replacement
Exterior LightsComponent Location Index .......................Circuit DiagramDaytime Running Lights ControiUnit Input Test (Canada) ........................Headlight Ad,ustment .................. .. .....Headlighr Replacement ..............................Combination Light SwitchTest/ReplacementBulb ReplacementTaillight Replacement ..........................High Mount Brake Light Replacement ......License Plate Light Replacement ..............Side Marker Light Replacement ................Brake Pedal Position Switch Test ..............Side Turn Signal Light Replacement ........
Turn Signal/HazardFlasher SystemComponent Location Index .......................Circuit DiagramTurn Signal/Hazard Relay lnputTest ........Hazard Warning Switch Test
22,3
22-7
22-13
22-44
22-46
22-4A
22-49
22-50
22-51
22-53
22-5422-5622-5422 6322-64
22-64
22-6522 61
22-6822--71
22-7 622-7422-79
22-AO22-4122-8222-4222-4322-4322-4422-84
22-8522 A622-8722-88
22-10422-105
22-10622-107
Entry Lights control systemComponent Location Index ....................... 22-89Circuit Diagram ......... 22 90lgnition Key Switch Test .....................,...... 22-9'llgnition Key Light Test ............................... 22-91Control Unit Input Test ..........,.................... 22 92
Interior LightsComponent Location Index ....................... 22-94Circuit Diagram ......... 22-95Ceiling LighVSpotlightsTesVReplacement ................................... 22-96Rear Ceiling Light TesVReplacem ent ........ 22-96Cargo Area Light Test/Replacem ent ......... 22-97Hatch Latch Switch Test ..,..,....................... 22-97
*Audio SystemComponent Location Index ....................... 22-98Circuit Diagram ......... 22,99Audio Unit Removal/lnstallation ............... 22-1OOAudio Unit Connector Replacement ......... 22-101Speaker Replacement ................................ 22-102Roof Antenna Rep1acement ....................-.. 22-103
Rear Window DefoggerComponent Location Index ...........Circuit Diasram .. ....... .. ..... ....... ...:::::.::.::.Function TestDefogger Wire Repair .................................Noise Condenser CapacityTest ................
MoonroofComponent Location Index ....................... 22-1OBCircuit Diagram ......... 22-109Moonroof Control Unit Input Test ............. 22-'l10Switch TesVReplacement ........,.....,........... 22-1 12Motor Test ................. 22-112Limit Swilch Test ...... 22-'l'13Auto-stop Switch Test ................................ 22-1 13
Power MirrorsComponent Location Index ....................... 22-114Circuit Diagram ......... 22-115Function Test ............. 22-116Power Mirror Switch Test .......................... 22-ll7Power Mirror Actuator Test ....................... 22-117Power Mirror Actuator Replacement ........ 22-11A
* HornsComponent Location Index ....................... 22-120Circuit Diagram ......... 22-121Horn TesVReplacement ...........................-. 22-122Horn Switch Test .,.... 22-122
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Connectors and Harnesses
Engine Wire Harness
Camshaft position (CMP) sensorLllr sensorEC[,4 connector AECI/l connector BEngine coolant temperature (ECT)
sensorEngine oil pressure switchEVAP canister purge valveldle air control (lAC)valve
lgnition coil No. llgnition coil No. 2lgnition coil No. 3lgnition coil No. 4Iniector No. 1Inlector No.2Iniector No.3Iniector No. 4Intake air temperature {lAT) sensor
TDC sensorThrottle position (TP) sensorVehicle speed sensor (VSSI
VTC oil control solenoid valveVTEC oil pressure switchVTEC solenoid valvec 101
c102
233
242
Transmission housingLeft side of engineRight side ofengineUnder glove boxUnder glove boxLeft side of engine
Bight side oI engineLeft side of intake manifoldLeft side of intake manifoldMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine compartmentMiddle of engine companment
28
1845672524201912
811102729303
22
12333332222233
322220
Left side of intake manifoldLeft side of engineLeft side of intake manifoldTransmission housingRight side o{ engineRight side of engineRight side of engineUnder right side of dash
Front of engine companment
Front of engine compartment
ECM wire harness {see page22-321Starter subharness (see page22-15)Starter subharness (see page22 151
Connector to Harness Index (cont'dl
22-16

Gauges
\-Component Location Index
PARKING BRAKE SWITCHpage 19-10
FUEL GAUGE SENDINGpage 11-156ENGINE OIL PRESSURE SWITCHpage 8-4
GAUGE ASSEMBLYSelJ-diaqnostic Procedure, page 22-56Gauqe dulb Replacement, page 22 63Rep6cement, page 22-64Coolant Temperature GaugeTroLrbleshooting, page 22'64
BRAKE FLUID LEVEL SWITCHpage 19-10VEHICLE SPEED SENSOR {VSS)Troubleshooting, page 22-65Beplacement, page 22-67
22-54
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